A. Field of Invention
This invention pertains to a sensor used for triggering passenger restraint system in a motor vehicle such an air bag system, and more particularly to a self-contained mechanical sensor with disarming means whereby the sensor can be set off only when it is installed within a passenger restraint system.
B. Description of the Prior Art
Sensors for passenger restraint systems are used to detect passenger restraint systems for detecting a crash. These sensors must be able to discriminate between sudden changes in the velocity of a motor vehicle due to normal operations, and abrupt velocity changes which may result in injury to the passengers. These sensors are often placed in the crush zone of the vehicle because in this zone it is easier to discriminate between acceptable and dangerous velocity changes. However inherently such sensors are less reliable because they must be coupled electrically for mechanically with the rest of the restraint system. Several sensors have been suggested which are made physically integral with the passenger restraint system. In this manner the need for long electrical or mechanical coupling means is eliminated. However, until now, all these systems were complicated to make.
For example U.S. Pat. No. 4,167,276 discloses a sensor relying on a rolamite ball arrangement to sense a crash. The patent also discloses a complicated automatic interlock coupled to the rolamite ball arrangement.
Commonly assigned U.S. Pat. No. 4,666,182 discloses an all mechanical sensor with multiple inertial masses for the sake of redundance.